Abstract: A liquid crystal display apparatus includes a liquid crystal display panel which indicates information represented by a contrast of the segments of the liquid crystal display when a drive voltage is applied to the display. A temperature meter measures the temperature of the LCD panel and the ambient temperature. A drive voltage setting device sets the drive voltage to be voltage to be applied to the LCD panel so as to maintain a constant contrast in accordance with the temperature value measured by the temperature meter. A drive voltage supply supplies the drive voltage set by the drive voltage setting device to the LCD panel.

Abstract: An electrophotographic printer is capable of using a plurality of types of continuous form recording media having different page lengths, respectively. In the printer, a photoconductive member is charged and exposed to light carrying image data to form a latent image. In operation, one of the plurality of types of recording media is selected, and a portion of the photoconductive member corresponding to a page of the selected one of the plurality of types of recording media is exposed to light. In another embodiment, a laser beam printer utilizes a continuous-form recording sheet, wherein two control members are provided for, respectively, controlling the recording sheet so as to be discharged from the printing device after a printing operation, and for controlling the recording sheet so as to be located at a position from which a printing operation is restarted. Thus, recording sheets are not wasted when printer output is started.

Abstract: An electrophotographic printer is capable of using a plurality of types of continuous form recording media having different page lengths, respectively. In the printer, a photoconductive member is charged and exposed to light carrying image data to form a latent image. In operation, one of the plurality of types of recording media is selected, and a portion of the photoconductive member corresponding to a page of the selected one of the plurality of types of recording media is exposed to light. In another embodiment, a laser beam printer utilizes a continuous-form recording sheet, wherein two control members are provided for, respectively, controlling the recording sheet so as to be discharged from the printing device after a printing operation, and for controlling the recording sheet so as to be located at a position from which a printing operation is restarted. Thus, recording sheets are not wasted when printer output is started.

Abstract: A data recovery device is employed in a printer using a continuous form recording medium for reprinting data after printing has been interrupted. In the data recovery device, the number of pages remaining in a predetermined area of the feed path of the recording medium is counted. A plurality of page buffers are sequentially read out and printed. The printing operation is controlled such that the one of the data storing means from which the data is read out and printed by the printing means is identified based on the number of the pages remaining in the predetermined area.

Abstract: A temperature control system is employed in a electrophotographic printer for controlling the temperature of a heat roller. In the system, the temperature of the heat roller is kept in a predetermined range of an operable range when printing is executed, and kept in a predetermined range of a standby range, which is lower than the operable range, when printing is unexecuted. The temperature of the heat roller is controlled to be raised up to the upper limit of the operable range before it is changed to be in the standby range when printing is terminated.

Abstract: A storage vessel detecting mechanism is used for detecting an error condition of a storage vessel, which is detachably fitted in a main apparatus. The vessel is movably fitted in the main apparatus, and one end of a movable member, which is pivoted, is engaged with the vessel. The other end of the movable member is located between first and second positions when the vessel is not installed and when the vessel is accommodating a predetermined amount of substances therein. It is determined whether the other end of the movable member is located in a predetermined range. An error condition of the vessel is detected when the other end of the movable member is located at a position other than in the predetermined range.

Abstract: In an electrophotographic printer, a toner image formed on a photoconductive member is transferred onto a recording medium by charging the recording medium and by making the charged recording medium contact the toner image formed on the photoconductive member. A transfer charger for charging the recording medium is arranged in such a fashion that the transfer charger faces the recording medium at the upstream-side portion, with respect to the feeding direction of the recording medium, of an area where the photoconductive member and the recording medium contact. Therefore, the recording medium is charged at the upstream side of the portion with respect to the lateral center of the portion where the recording medium and the image carrying means contact.

Abstract: A power controlling device capable of controlling the supply power to a drive system and to a control system for controlling the drive system. The power controlling device is provided with a main switch capable of turning on and turning off the power supplying device. When the power supplying device is turned off by the main switch, the drive system is turned off before the control system is turned off.

Abstract: A video signal composing circuit and method for aligning scanned CCD's in an optical reading device in which plural scanned CCD's are arranged in a line parallel to a reading surface. Clock pulses are counted which correspond to the scanning of the CCD's and compared with values set by plural switch groups. The outputs of the comparison circuits are coupled through a logic circuit which combines and gates the individual video output signals from the CCD's to produce a composite video signal which is free of overlap in video signals between adjacent CCD's.